The invention relates generally to dairy products, and particularly to methods and apparatus for reforming cheese products and other dairy products.
In the manufacture of chunk cheese products, large blocks of natural cheese weighing on the order of about 600 to 700 lbs. are divided into smaller chunks for retail sale. Parts of the large blocks are left as irregularly shaped pieces, referred to as trim or offcuts.
In the past, such pieces have often been used as ingredients for process cheese, or have been formed into shreds. However, the value of the resulting product, be it shredded cheese or process cheese, is generally lower than the value of blocks or chunks of natural cheese. Substantial effort has been devoted to developing methods for reforming such pieces into larger blocks of natural cheese. It is believed that combining small pieces into a cohesive larger chunk requires a certain amount of working of the cheese. Without sufficient working, the end product may not be cohesive, i.e., the chunk may have visible divisions, and may separate along such divisions or crumble when sliced or otherwise handled by the consumer. Excessive working, however, results in xe2x80x9coiling offxe2x80x9d, i.e., separation of oil, and/or maceration, resulting in an unacceptable end product. One aspect of the invention is to provide a method and apparatus for reforming small cheese pieces such as trim or offcuts, and/or other dairy products, into chunks of natural cheese, or into other solid, cohesive dairy products of firm texture, without maceration or separation of oil.
Ross, U.S. Pat. No. 3,727,308, discloses apparatus for reconstituting cheese trimmings into a solid block. Cheese trimmings are placed in a hopper and forced through holes in a plate under the action of an auger and knife.
Sadler, U.S. Pat. No. 4,382,969, discloses a method for treating cheese off-cuts wherein the off-cuts are first cut into small chips, and then pressed in an evacuated environment to form a reconstituted block of cheese. Sadler states that the apparatus described in the above-discussed Ross patent has several drawbacks in that the displacement of the trimmings using a helical auger results in considerable working of the cheese which can detract from the characteristics of the end product. The apparatus of Sadler employs a ram, rather than an auger, to advance the cheese. In Sadler, the cheese undergoing processing remains in the range of 8xc2x0 C. to 12xc2x0 C. This temperature control is achieved, if necessary, by including a cooling jacket around the nozzle 32 at the outlet end of the equipment.
U.S. Pat. No. 4,185,126, discloses a process of reconstituting cheese trimmings into horns by grinding the trimmings into a particulate mass at a temperature which inhibits bacteria growth, then ramming the particulate mass into a closed mold.
Runge et al., U.S. Pat. No. 3,562,910, discloses a method for manufacture of natural cheese from curd. The Runge apparatus includes a curd transfer device that includes a pair of co-acting helical cams and a close fitting housing therefor. The helical cams are shown as intermeshing. In the Runge patent, the cams force the curd into a forming tube to establish knitting. The tube appears to be of uniform circular cross-section. Its length is about 5 feet to 20 feet. Heating of the tube to a temperature sufficient to melt the fat of the cheese curd is said to cause oiling off which effects lubrication of the walls of the tube and lowers the effective resistance of the tube. This patent states that undue oiling off is undesirable, and that the temperature of the tube surface adjacent to the cheese should not exceed about 160xc2x0 F.
Miller et al., U.S. Pat. No. 4,620,838, assigned to Kraft, Inc., discloses use of a ram for forcing cheese through a perforated die plate to form shreds.
U.S. Pat. No. 5,768,970 discloses an ultrasonic cutting system for cutting of foodstuffs including cheese.
It is a general object of the invention to provide a novel and improved method and apparatus for reforming small pieces of cheese or other dairy product into larger chunks with appearance, taste and texture similar to fresh cut natural chunks or other products having enhanced value.
In accordance with the invention, a method and apparatus for reforming small pieces of natural cheese or other dairy products, such as shreds, trim, or offcuts, are provided wherein the small pieces are fed through a mechanical pump and a die that form the product into a cohesive larger chunk. The mechanical pump and the die preferably operate such that natural cheese pieces may be formed into the larger chunk of natural cheese having a very similar texture and appearance to that of the original product.
In a preferred embodiment of the invention, the mechanical pump mixes and folds the small pieces of cheese or other dairy products into a viscous mass without excessive separation of oil. More particularly, the mechanical pump in the preferred embodied produces a viscous mass with virtually no separation of oil. Any oil that does separate from the product is of a minimal amount, e.g., less than 0.1% of the oil in the cheese pieces. The mechanical pump then feeds the viscous mass through the die. The die preferably has a region of substantially uniform cross-section. The ratio of the length of the region to its smallest cross-sectional dimension, e.g., its height, is preferably about 4:1. The region of substantially uniform cross-section is maintained at an elevated temperature to reduce drag and improve the appearance of the end product.
The method and apparatus of the invention preferably enables offcuts, trim and other small pieces of natural cheese or other dairy products to be reformed into cohesive larger chunks of natural cheese, without addition of water, salt or other ingredients, and without separation of oil or maceration. The configuration and speed of operation of the mechanical pump are selected so that it does not overwork the smaller pieces when mixing and folding them into a viscous mass. The substantially uniform region of the die forms the viscous mass into the desired shape with well defined edges. The die temperature reduces friction and produces a thin surface seal about the exterior surface of the larger chunk without excessive separation of oil from the surface of the larger chunk.
In the preferred embodiment of the invention, the extrudate is fed through one or more slitting and cutting stations after emerging from the die. The slitting and cutting stations preferably use ultrasonic cutters to leave clean, smooth, sealed edges with no fines and a thin surface seal to minimize moisture or volatile losses as well as enhance the product appearance.